Need to choose a protable amp +/- DAC... What is your favorite, and why?

[americankami]

Hey folks.  I'm new here. 
 
This all started three days ago because I was looking for a headphone amp for my laptop... Now I'm the proud owner of a pair of AKG K702s, and I still need a portable amp!  I can see already this is going to be an expensive hobby... 

 
So after a lot of reading over the weekend, I think I've got it narrowed down to an Ibasso PB2 or an RSA SR-71/71A/71B.
 
I think I'm leaning more towards the Ibasso because of the price and the ability to swap out opamps and buffers.
 
Having both balanced and 1/8" or 1/4" outputs would be a huge plus, as I may want to step up to bigger and better cans in the future.
 
This is going to be my one do-all amp for both laptop and portable for the time being, as well as some band stuff if necessary.  $650 is right around my price ceiling right now.
 
Here are my questions:
 
1)  What's your current favorite sub $651 portable headphone amp, and why?  If you have another favorite that's over that price, I'd like to hear what that is as well. 
 
2)  Do you also use a DAC such as the Ibasso DB2, do you feel that it's vital to do so, and why?
 
3)  If you had to pick between the the Ibasso and the RSA, which would you choose and why?
 
Please limit your responses only to gear that you've either listened to and played with, or outright owned at some point. 
 
Thanks folks, and looking forward to your responses!

 

[punks15]

1. ALO Continental. Smooth, clear, nice soundtaging and superb midrange
2. Yes, DAC is also  a vital point. Upgrading DAC will improve your source quality
3. RSA, it's simply my personal preferences that tend to RSA

 

[liamstrain]

Not sure on pricing, but Ray is releasing the Intruder - which appears to be a portable balanced DAC/AMP - if it's anywhere close to the SR-71 series amps, it should be quite a product.
http://www.raysamuelsaudio.com/products/intruder
 
I do personally think for computer audio, an external dac is a good thing. I like to mix and match though, so I prefer a dac that is independent of the amplifier, so I can swap out different amps. 
 
But I'm not shooting for extreme portability here, or at least, not an all-in-one.